Ensure that 'errno' is saved and restored by all signal handlers that
might change it. Experimentation shows that the signal handler call mechanism does not save/restore errno for you, at least not on Linux or HPUX, so this is definitely a real risk.
This commit is contained in:
Tom Lane
parent
c431db9714
commit
5491233f52
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.73 2000/11/28 23:27:54 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.74 2000/12/18 17:33:40 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -589,6 +589,7 @@ AtAbort_Notify()
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void
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Async_NotifyHandler(SIGNAL_ARGS)
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{
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int save_errno = errno;
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/*
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* Note: this is a SIGNAL HANDLER. You must be very wary what you do
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@ -637,6 +638,8 @@ Async_NotifyHandler(SIGNAL_ARGS)
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*/
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notifyInterruptOccurred = 1;
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}
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errno = save_errno;
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}
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/*
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@ -11,7 +11,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.198 2000/12/03 20:45:34 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.199 2000/12/18 17:33:40 tgl Exp $
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*
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* NOTES
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*
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@ -217,7 +217,7 @@ static int initMasks(fd_set *rmask, fd_set *wmask);
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static char *canAcceptConnections(void);
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static long PostmasterRandom(void);
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static void RandomSalt(char *salt);
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static void SignalChildren(SIGNAL_ARGS);
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static void SignalChildren(int signal);
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static int CountChildren(void);
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static bool CreateOptsFile(int argc, char *argv[]);
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@ -1303,10 +1303,13 @@ reset_shared(unsigned short port)
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static void
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SIGHUP_handler(SIGNAL_ARGS)
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{
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int save_errno = errno;
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if (Shutdown > SmartShutdown)
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return;
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got_SIGHUP = true;
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SignalChildren(SIGHUP);
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errno = save_errno;
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}
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@ -1317,6 +1320,8 @@ SIGHUP_handler(SIGNAL_ARGS)
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static void
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pmdie(SIGNAL_ARGS)
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{
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int save_errno = errno;
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PG_SETMASK(&BlockSig);
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if (DebugLvl >= 1)
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@ -1330,8 +1335,12 @@ pmdie(SIGNAL_ARGS)
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* Send SIGUSR2 to all children (AsyncNotifyHandler)
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*/
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if (Shutdown > SmartShutdown)
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{
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errno = save_errno;
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return;
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}
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SignalChildren(SIGUSR2);
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errno = save_errno;
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return;
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case SIGTERM:
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@ -1342,24 +1351,34 @@ pmdie(SIGNAL_ARGS)
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* let children to end their work and ShutdownDataBase.
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*/
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if (Shutdown >= SmartShutdown)
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{
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errno = save_errno;
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return;
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}
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Shutdown = SmartShutdown;
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tnow = time(NULL);
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fprintf(stderr, "Smart Shutdown request at %s", ctime(&tnow));
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fflush(stderr);
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if (DLGetHead(BackendList)) /* let reaper() handle this */
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{
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errno = save_errno;
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return;
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}
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/*
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* No children left. Shutdown data base system.
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*/
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if (StartupPID > 0 || FatalError) /* let reaper() handle
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* this */
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{
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errno = save_errno;
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return;
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}
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if (ShutdownPID > 0)
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abort();
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ShutdownPID = ShutdownDataBase();
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errno = save_errno;
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return;
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case SIGINT:
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@ -1371,7 +1390,10 @@ pmdie(SIGNAL_ARGS)
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* and exit) and ShutdownDataBase.
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*/
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if (Shutdown >= FastShutdown)
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{
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errno = save_errno;
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return;
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}
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tnow = time(NULL);
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fprintf(stderr, "Fast Shutdown request at %s", ctime(&tnow));
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fflush(stderr);
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@ -1384,11 +1406,13 @@ pmdie(SIGNAL_ARGS)
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fflush(stderr);
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SignalChildren(SIGTERM);
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}
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errno = save_errno;
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return;
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}
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if (Shutdown > NoShutdown)
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{
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Shutdown = FastShutdown;
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errno = save_errno;
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return;
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}
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Shutdown = FastShutdown;
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@ -1398,11 +1422,15 @@ pmdie(SIGNAL_ARGS)
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*/
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if (StartupPID > 0 || FatalError) /* let reaper() handle
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* this */
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{
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errno = save_errno;
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return;
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}
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if (ShutdownPID > 0)
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abort();
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ShutdownPID = ShutdownDataBase();
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errno = save_errno;
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return;
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case SIGQUIT:
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@ -1435,18 +1463,18 @@ pmdie(SIGNAL_ARGS)
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static void
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reaper(SIGNAL_ARGS)
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{
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/* GH: replace waitpid for !HAVE_WAITPID. Does this work ? */
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int save_errno = errno;
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#ifdef HAVE_WAITPID
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int status; /* backend exit status */
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#else
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union wait status; /* backend exit status */
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#endif
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int exitstatus;
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int pid; /* process id of dead backend */
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PG_SETMASK(&BlockSig);
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/* It's not really necessary to reset the handler each time is it? */
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pqsignal(SIGCHLD, reaper);
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if (DebugLvl)
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fprintf(stderr, "%s: reaping dead processes...\n",
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@ -1499,12 +1527,11 @@ reaper(SIGNAL_ARGS)
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CheckPointPID = 0;
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checkpointed = time(NULL);
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pqsignal(SIGCHLD, reaper);
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errno = save_errno;
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return;
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}
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CleanupProc(pid, exitstatus);
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}
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pqsignal(SIGCHLD, reaper);
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if (FatalError)
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{
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@ -1513,9 +1540,15 @@ reaper(SIGNAL_ARGS)
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* Wait for all children exit, then reset shmem and StartupDataBase.
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*/
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if (DLGetHead(BackendList))
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{
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errno = save_errno;
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return;
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}
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if (StartupPID > 0 || ShutdownPID > 0)
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{
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errno = save_errno;
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return;
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}
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tnow = time(NULL);
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fprintf(stderr, "Server processes were terminated at %s"
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"Reinitializing shared memory and semaphores\n",
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@ -1526,18 +1559,26 @@ reaper(SIGNAL_ARGS)
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reset_shared(PostPortNumber);
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StartupPID = StartupDataBase();
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errno = save_errno;
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return;
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}
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if (Shutdown > NoShutdown)
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{
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if (DLGetHead(BackendList))
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{
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errno = save_errno;
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return;
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}
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if (StartupPID > 0 || ShutdownPID > 0)
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{
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errno = save_errno;
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return;
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}
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ShutdownPID = ShutdownDataBase();
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}
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errno = save_errno;
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}
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/*
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@ -2002,6 +2043,7 @@ ExitPostmaster(int status)
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static void
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dumpstatus(SIGNAL_ARGS)
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{
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int save_errno = errno;
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Dlelem *curr;
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PG_SETMASK(&BlockSig);
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@ -2015,6 +2057,7 @@ dumpstatus(SIGNAL_ARGS)
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fprintf(stderr, "\tsock %d\n", port->sock);
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curr = DLGetSucc(curr);
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}
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errno = save_errno;
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}
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/*
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.87 2000/12/18 00:44:47 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.88 2000/12/18 17:33:41 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -48,10 +48,11 @@
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* This is so that we can support more backends. (system-wide semaphore
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* sets run out pretty fast.) -ay 4/95
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*
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* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.87 2000/12/18 00:44:47 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.88 2000/12/18 17:33:41 tgl Exp $
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*/
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#include "postgres.h"
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#include <errno.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include <signal.h>
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@ -298,7 +299,7 @@ InitProcess(void)
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}
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/* -----------------------
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* get off the wait queue
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* get process off any wait queue it might be on
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* -----------------------
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*/
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static bool
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@ -623,10 +624,11 @@ ins:;
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waitQueue->size++;
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lock->waitMask |= myMask;
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SpinRelease(spinlock);
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MyProc->errType = NO_ERROR; /* initialize result for success */
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SpinRelease(spinlock);
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/* --------------
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* Set timer so we can wake up after awhile and check for a deadlock.
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* If a deadlock is detected, the handler releases the process's
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@ -826,6 +828,7 @@ ProcAddLock(SHM_QUEUE *elem)
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void
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HandleDeadLock(SIGNAL_ARGS)
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{
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int save_errno = errno;
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LOCK *mywaitlock;
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LockLockTable();
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@ -846,6 +849,7 @@ HandleDeadLock(SIGNAL_ARGS)
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MyProc->links.next == INVALID_OFFSET)
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{
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UnlockLockTable();
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errno = save_errno;
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return;
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}
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@ -858,6 +862,7 @@ HandleDeadLock(SIGNAL_ARGS)
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{
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/* No deadlock, so keep waiting */
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UnlockLockTable();
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errno = save_errno;
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return;
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}
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@ -891,6 +896,7 @@ HandleDeadLock(SIGNAL_ARGS)
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* conditions. i don't claim to understand this...
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*/
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UnlockLockTable();
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errno = save_errno;
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}
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void
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.195 2000/12/18 00:44:47 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.196 2000/12/18 17:33:41 tgl Exp $
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*
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* NOTES
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* this is the "main" module of the postgres backend and
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@ -984,8 +984,11 @@ FloatExceptionHandler(SIGNAL_ARGS)
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static void
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QueryCancelHandler(SIGNAL_ARGS)
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{
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int save_errno = errno;
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QueryCancel = true;
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LockWaitCancel();
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errno = save_errno;
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}
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void
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@ -1646,7 +1649,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[], const cha
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if (!IsUnderPostmaster)
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{
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puts("\nPOSTGRES backend interactive interface ");
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puts("$Revision: 1.195 $ $Date: 2000/12/18 00:44:47 $\n");
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puts("$Revision: 1.196 $ $Date: 2000/12/18 17:33:41 $\n");
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}
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/*
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@ -3,7 +3,7 @@
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*
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* Copyright 2000 by PostgreSQL Global Development Group
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*
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* $Header: /cvsroot/pgsql/src/bin/psql/common.c,v 1.28 2000/12/15 17:54:43 petere Exp $
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* $Header: /cvsroot/pgsql/src/bin/psql/common.c,v 1.29 2000/12/18 17:33:42 tgl Exp $
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*/
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#include "postgres.h"
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#include "common.h"
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@ -258,6 +258,8 @@ volatile bool cancel_pressed;
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|||
void
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handle_sigint(SIGNAL_ARGS)
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{
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int save_errno = errno;
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/* Don't muck around if copying in or prompting for a password. */
|
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if ((copy_in_state && pset.cur_cmd_interactive) || prompt_state)
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return;
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@ -274,6 +276,7 @@ handle_sigint(SIGNAL_ARGS)
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|||
write_stderr("Could not send cancel request: ");
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write_stderr(PQerrorMessage(cancelConn));
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||||
}
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||||
errno = save_errno; /* just in case the write changed it */
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||||
}
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#endif /* not WIN32 */
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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||||
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-connect.c,v 1.154 2000/12/07 02:04:30 tgl Exp $
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||||
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-connect.c,v 1.155 2000/12/18 17:33:41 tgl Exp $
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||||
*
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||||
*-------------------------------------------------------------------------
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||||
*/
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|
@ -2084,6 +2084,7 @@ PQresetPoll(PGconn *conn)
|
|||
* malloc/free are often non-reentrant, and anything that might call them is
|
||||
* just as dangerous. We avoid sprintf here for that reason. Building up
|
||||
* error messages with strcpy/strcat is tedious but should be quite safe.
|
||||
* We also save/restore errno in case the signal handler support doesn't.
|
||||
*
|
||||
* NOTE: this routine must not generate any error message longer than
|
||||
* INITIAL_EXPBUFFER_SIZE (currently 256), since we dare not try to
|
||||
|
|
@ -2093,6 +2094,7 @@ PQresetPoll(PGconn *conn)
|
|||
int
|
||||
PQrequestCancel(PGconn *conn)
|
||||
{
|
||||
int save_errno = errno;
|
||||
int tmpsock = -1;
|
||||
struct
|
||||
{
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||||
|
|
@ -2109,6 +2111,7 @@ PQrequestCancel(PGconn *conn)
|
|||
strcpy(conn->errorMessage.data,
|
||||
"PQrequestCancel() -- connection is not open\n");
|
||||
conn->errorMessage.len = strlen(conn->errorMessage.data);
|
||||
errno = save_errno;
|
||||
return FALSE;
|
||||
}
|
||||
|
||||
|
|
@ -2154,6 +2157,7 @@ PQrequestCancel(PGconn *conn)
|
|||
close(tmpsock);
|
||||
#endif
|
||||
|
||||
errno = save_errno;
|
||||
return TRUE;
|
||||
|
||||
cancel_errReturn:
|
||||
|
|
@ -2168,6 +2172,7 @@ cancel_errReturn:
|
|||
close(tmpsock);
|
||||
#endif
|
||||
}
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||||
errno = save_errno;
|
||||
return FALSE;
|
||||
}
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||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue